“The Age of Amphibians” – Amphibians and reptiles dominant. Gymnosperms dominant plant life.The continents merge into a single super-continent, Pangaea. Phtyoplankton and plants oxygenate the Earth’s atmosphere to close to modern levels. The Permian ended with largest mass extinction. Trilobites go extinct, as do 50% of all animal families, 95% of all marine species, and many trees, perhaps caused by glaciation or volcanism.